Precipitation Potential Placement is a derived parameter combining precipitable
water and low-level mean RH to help better place where rainfall will occur.
Research has been published in the National Weather Association Digest in 2003
and stems from research and operational use of this product originally
developed at NESDIS and Rod Scofield for satellite rainfall estimates dating
back to 1981.

Rainfall is usually maximized where the best low level convergence and instability
overlay with the highest values for this parameter.